Researchers have developed a promising new urine test that could revolutionize the way prostate cancer is diagnosed and managed, potentially sparing many men from undergoing unnecessary biopsies. Typically, when a prostate-specific antigen (PSA) blood test yields abnormal results, the next step often involves a prostate biopsy. While biopsies can confirm or rule out cancer, they are invasive and can detect slow-growing tumors that may not require immediate treatment.
To address these challenges, scientists at the University of Michigan developed the MyProstateScore 2.0 (MPS2) test, which screens urine samples for 18 different genes associated with high-grade prostate tumors. Dr. Arul Chinnaiyan, a professor at the University, explained that a negative result on the MPS2 test indicates a high likelihood of not having aggressive prostate cancer, offering reassurance without the need for invasive procedures.
The development of MPS2 involved extensive research and validation. Initially, researchers identified 54 genes overexpressed in Grade Group 2 (GG2) or higher prostate cancers from a database of 58,000 prostate cancer-associated genes. After testing these genes on urine samples from 761 men with elevated PSA levels, they identified 18 genes consistently associated with high-grade cancer. This set of genes now forms the basis of the MPS2 test.
Validation studies using over 800 additional urine samples confirmed MPS2’s accuracy in identifying Grade Group 2 and higher cancers. The test correctly identified 95% of GG2 cancers and 99% of GG3 or higher cancers. Incorporating estimates of prostate size further improved test accuracy, potentially reducing unnecessary biopsies by 37% to 41%.
Compared to other diagnostic tools like the Prostate Health Index (PHI) and multi-parametric MRI scans, MPS2 offers distinct advantages. Unlike MRI scans, which require specialized equipment and expertise not always available in all settings, MPS2 provides a straightforward numerical risk estimate that can guide clinical decisions. This accessibility could be particularly beneficial for men in rural or underserved areas who may lack access to advanced imaging facilities.
Dr. Boris Gershman, a urologist at Beth Israel Deaconess Medical Center, acknowledged the promising performance of MPS2 compared to PSA alone. However, he noted the challenge of determining the threshold for recommending biopsies based on a continuous risk score rather than a binary MRI result. Dr. Marc Garnick, a professor at Harvard Medical School, highlighted the potential of MPS2 to enhance precision in prostate cancer diagnosis and treatment decisions, particularly in assessing the clinical significance of detected cancers.
In conclusion, the MPS2 urine test represents a significant advancement in prostate cancer diagnostics, offering a non-invasive and reliable method to identify high-grade tumors. As research continues and more prostate cancer-associated genes are identified, MPS2 holds promise in improving patient care by reducing unnecessary biopsies and guiding appropriate treatment strategies based on individual risk profiles.
